Cojgor bhotogbaphy



F. E. n/Es.

COLOR PHOTOGRAPHY.

APPLICATION FILI-:n Aue.9. 1911.

15306,@9@ Patented Jun@ 17, 1919.

Fig. Z

7, Fed sens/'Mfg aaai/27g 6, Carr/fer ('yZaJJ/ www@ - blage or setof flexible or.

To all whom t may concern.' I

Be itknown that I, Fnsmo EUGENE Ivns, a c'itizen of the United States residing at Philadelphia, in thecounty of .lhiladelphia and State of Pennsylvania, have invented certain new and useful Improvements in Color Phottlgraph of whichthe following is a speci cation, reference being had therein to the accompanying drawing.

This invention -relates to the art ofcolor photography, and more novel system of color photography and a fplate-pack ,having the advantages lof greater efficacy and more correct resulting color photographs than heretofore. A lparticular object is to minimize the tendency to halation in photoaphic plate-packs.l By the term plate-pac refer to any assemparticularly to a rigid plates, films or other members,v whether two,A three or more .in number, an exam shown in my prior Patent l o. 927,244, dated July 6, 1909.

The. drawing which accompanies and forms part of this specification comprises' the generalnature of a Figure l showing color photography plate-pack and the dilliculty of diffusion which is known as halation, with inscriptions showing one embodiment ofthe-present invention; and Fig. 2 shows a modification thereof. In my. said prior patent the pack comp-rises a 4front member consisting of a transparent carrier or glass having` a blue sensitive coating at its rear face; a rear member consisting of a carrier having a'red sensitive coating at its front face; anda middle member provided with a green sensitive coating; there being a yellow layer or surface4 screen at the rear of or upon the blue sensitive coating to shield the other members from the blue light; and

there being a red layer or surface coating or screen in front of or'upon the red sensitive member to shield it from the green light.

Referring generally to the arrangement ofthe assemblage or pack El shown \in the figure or diagram, this comprises the rear member 2, the middle member 3, and thev front member 4, which are red, green, and blue sensitive, respectively. The rear member 2 comprises the glass or other carrier 6 bearing the red sensitive coating 7. The' member 3 comprises the green sensitive coat- Spcci-ilcation of Letters latent.

le of which isI the transmission v the rear,

l Patented lune 1W, 119m.

.application mea august s, 1911. serial no. maar.

ing 9 upon the celluloid or other carrier 10. he front member comprises the blue sensitive coating .12 upon the carrier 13.

The halatlon dilliculties arose from the fact that the light beama from the objective has .to pass through a plurality of sensitive catingsand one or more transparent carriers so that the light incident upon one coating might be difusely 'reflected frontward, for example, as indicated at L, L, in the diagram, so 'as to reach and be rearwardly reflected from the front surface of a transparent carrier as indicated at c, ci, so as to objectionably sensitive coatings. ll'ith a three member pack, one or both of the rear members, in-v clu-ding their lxaloid layers and their carrie-rs, tend to give the frontward reflections and each carrier tends-to reverse this st-ray light giving the injurious rearward reflection. Being due to rearward' reflections from front surfaces, this halation phenomenon may be'termed front halation and is quite different, because more serious, in color photography than theusual orrear halation encountered in ordi-nary photography.

This difficulty is -ahnost negligible with re' affect, one or more of the or its emulsion, as this e'ectively restrains of blue light in any direction. -At the same .time this serves as a yellow screen, taking the place of the superlicial yellow layer of my. prior patent and protecting'the rear sensitive members against the blue light. i

As u 'l1 be seen from the diagram, the really serious halation occurs with respect to that is the green and the red sensitive members. The condition described with. respect to the front member of the pack pack does not pply to the other members,

for diil'erent reasons, lfor example, beca-use silver bromid'is able to |diusely reect a ofthe pack,

to minimize the halation so that it will no great' deal oi red and green light, and to difrusely transmit a considerable percentage of 'red light?I as would a piece of thin yellow paper; and of this una'bsorbed actinic light a substantial amunt' is 'reiected frontward and thence rearward to the sensitive surfaces with such diffusion as to produce objectionable halation in the middle and rear members The present invention operates longer be objectionable, and without preventing due actinic act-ion in making the ex- I .tual gain is far greater, due to the fact that duce into the body of or in front of the red .sensitive layer 7 a small amount of'm'inusred or 'blue colorin y matter, preferably a water-soluble dye. ilel this to a slight extent prolongs the necessary exposure, it will serve to reduce the reiection and theref fore halation to about four times that extent. For'example, if a blue surface screening ,of the red sensitive member be sufficiently strong to reduce the action of red light by this would serve to reduce the 'amount Vof light reflected and capable of halation, to labout 12%%, eliminating 90% `of thehalation.

I prefer, however, thattheblue s creenin dye be contained or diffused inthe body o the colloid'layer 7, and in that-case the acthe screening of the sensitive particles through the: layer is progressive with, the

, depth, so that such screening reduces the sen-I sitive factor orspeed to a 'quite immaterial .I extent while very edectively reducing the refiection or halation factors. A slightly lower density in the negative would result, butV this would be unobjectionable! and in many cases advantageous.,

Obviously, the introduction of the minust red la er or ingredient Amay be combined Mi viously .referred tol which serves to exclude.

with t e introduction of the red screen pregreen light. A combination of red-'introduced for screeningpurposes as before mentioned, and i minus-red for reducing halation, may be secured by adopting a suitable g tone of color which sometimes might be answered by a neutral or gray which couldl -be 'aeplied supericially or through the body1 of Vmisil-.ive layer 7.-

Substantially the same remarks would. ap-

'ply to the middle or gi'een sensitive member 3, and a water-soluble dye of a minus-green or redcolor could be introduced withinthe body off the layer to minimize the halation produc-mg reflections.

The non-actinic ingredients or dyes may be added either to the emulsions before coa-ting, or ysubsequently by bathing the plates for two `minutes in an aqueous solution of the dyes and then drying.

Suitable dye baths for `these purposes-are as follows: For the green sensitive film:

"water, 738 c. c.`;.alcohol, 170 c.v c.; Sodium salt of 'p-sulonaphthalene-azo-a-naphtholl )snlfonic acid, otherwise known as carmosin 1 declgram. For the red sensitive film: water, 738 c. c.; alcohol, 170 c. c.; calcium dibenzyldiamido-triphenyl-carbinol, otherwise known as patent blue, 1 centigram'.

By mtroducing these minus screening col- -ors merely as surface layers, the density of the members remains unalteredand 'the re ductlon' of halation is substantial althou h not so great as with body staining. T 'e halationreducing layers need not ,be in con. tact with the corresponding sensitive layers. For example, the minus-red. screening for the rear member .might lbe appliedat some peint fart-her 'forwardbr even at the front side of the front member 4, as seen. in'Fig. 2, in which case it would operate not by-reducthe rontward reiection Afrom thesilver id layers but the relative rearward2re iection :from the'fr'ont glass surface'. and it- 14 in optical contact with the glass 13 and of-4 similar refractive index.

, It will thus be seen that I have describe a system or method anda Jplatefpackernbodyingithe principles of the invention and attaining the advantages thereof, and other ,advantages will be apparent to those skilled Ain the art. Since many .matters of fdetaill such as the order ofthe ste s, the nature orI composition ofthe ingredlents, the selecf `tion and arrangement of the colors, .and

other features,may be variously modified without departing fromthe novel principles involved, I do not intend to limitr the invention to such features except in so far as specified in the appendedv` claims.

What is claimed is: .l

1. In color-photography, the, method of making aaplurality 'of color representing negatives from a plurallty or dilerently color-sensitized members, comprising screeni'ng one of said sensitive members by a nonactinic agent, assembling the members -with said` screened. membergbehind another of .said members, and exposing the assemblage so arranged,

- 2. The mama as in claim 1,- aad wherein" neeaee 3. A plate-pack for color photographyA comprising a pluralit of assembled sensitive members, a mem r behind the front4 member being screened against halation by a non-actinic agent.

\ corded by the screened member.

d. A platepack as in claim 3, and wherein the screening agent is a removable color material of color minus the color to be re- 5. A plate pack as in claim 3', and wherein the rear member is also-protected by a screen of the colorit is to record.

6. A.A plate-pack for color photography, comprising three members sensitive to ,the selected primaries respectively', one of the members behind the front member beingV screened against halation by a non-actinic agent.

7. A plate pack as in claim 6, and wherein allf the members 'behind the front member are so screened.

.8. A plate pack as in claim 6, and Wherein the rearmost member is partially .screened both against the color to be recordedand the complementaryl color.. z l

.9. As an element of a plate pack, a' sensi;- tive member having'a screen comprisin an agent of the color 1t is to record for exc uding other colors, and an agent of a color minus to said color for reducing halation.

10. As an element of a plate pack a sensitive member containing means for partially screening it both against the color it istorecord and the complementary colors.

11. A plate-pack comprising three members,. one sensitive tored and screened b a minus-red agent against halation, anot er sensitive to green and screened by va minusgreen agent against halation, and a. blue recording member assembled in front of the other two.

In testimony whereof, ll have ailxed my signature hereto.

FREDERIC EUGENE YVES.

.dil 

